1. Field
The present invention relates to a light emitting diode package and, more particularly, to a UV light emitting diode package and a method of fabricating the same.
2. Discussion of the Background
Gallium nitride-based light emitting diodes are widely used for display devices and backlight units. In addition, with low power consumption and long lifespan as compared with existing incandescent lamps or fluorescent lamps, applications of light emitting diodes have expanded to general lighting by replacing existing incandescent lamps, fluorescent lamps, and the like. Recently, light emitting diodes emitting deep ultraviolet (DUV) light having a wavelength of 365 nm or less are developed and can be widely applied to air and water sterilization, surface contaminant removal, optical sensors such as a bio-agent detector, UV curing of polymers, instruments for medicine and analysis, and the like.
In general, DUV light emitting diodes (LEDs) has a multi-quantum well structure which includes gallium nitride-based well layers containing Al between an n-type AlGaN layer and a p-type AlGaN layer to emit light of short wavelengths. Since UV light emitted from such a DUV LED can be easily absorbed by a typical sealing resin such as silicone or epoxy resins, it is difficult to seal the DUV LED using the sealing resin unlike a blue LED.
Accordingly, a package is generally used to protect an LED by mounting the LED on a metal stem and bonding a window-integrated cap to the metal stem in the related art. However, since such a stem package is expensive due to high material and manufacturing costs, attempts have been made to use low cost packages such as ceramic packages or general plastic packages as UV LED packages.
For example, with an LED placed in a cavity of a package body, the cavity may be sealed by attaching a lens to a package body using a bonding agent. The cavity is sealed by the package body, the lens and the bonding agent, thereby preventing external moisture and the like from entering the cavity. However, during attachment of the lens, the lens can be separated from the package body by compressed air within the cavity, thereby causing bonding failure. For example, when the lens is compressed on the package body using a lens holder with the bonding agent disposed between the lens and the package body, compressed air is generated within the cavity. When the lens holder is removed, the lens can be separated from the package body by the compressed air. Moreover, upon curing of the bonding agent, air pressure within the cavity can be increased due to expansion of air within the cavity, thereby causing separation of the lens from the package body.